The invention relates to an information transfer system, comprising a receiver and a transmitter for transferring an information signal to the receiver via a transfer medium, the information signal comprising main data and sub data, the sub data comprising coded text lines having a plurality of character codes, the receiver being provided with a character display unit for displaying characters defined by the character codes in the coded text lines, which display unit has a predetermined number of character display positions.
The invention further relates to a transmitter, a receiver and a record carrier for use in the system.
A system as described in the opening paragraph is inter alia known from EP-A-0,325,325. In this patent application a system is described in which the information signal is transferred via a record carrier, e.g. a Compact Disc or a digital audio tape, to an audio player. The player is provided with at least one multi-line display unit for displaying text lines defined by the coded text lines included in the sub data transferred. The number of character positions (digits) of the display unit is sufficient to display a full text line of forty characters. By means of the system additional information related to the main (audio) information reproduced can be displayed.
The full line display units are less suitable when small sized receivers, such as e.g. portable players and car radios, are used in the system, because in general there is not enough space available for such full line display units. Full line display units are also less suitable to be used on the remote controllers of the receivers. On the other hand it is also desirable that on that type of receivers and remote controllers additional information related to the reproduced main information can be displayed.
It is on object of the invention to provide means which enables that significant parts of the text information available in the sub data can also be shown on display units on small-sized receivers and remote controllers without the requirement of far-reaching amendments in the sub data format.
According to the invention this object is achieved for a system described in the openings paragraph which is characterized in that said predetermined number of character positions of the display unit is less than the number of character codes in the coded text lines, in that the coded text lines include control codes, the receiver being provided with display control means for controlling the display of characters corresponding to the character codes included in the coded text line in dependence on the said control codes.
In the system according the invention the information already available in the coded text lines included in the sub data for displaying on a full line display unit, can also be used for the display on a small sized display unit with a limited number of character positions. This has the advantage that the addition of coded text to the sub data for exclusive use in combination with a 1-line display with a limited number of digits is not required.
An embodiment of the system is characterized in that the receiver is provided with means for storing received coded text lines into a memory, and in that the control codes comprises horizontal scrolling control codes, the display control means of the receiver being adapted to initiate in response to the horizontal control codes a horizontal scroll of the characters of the coded text line stored in the memory.
By using a combination of a memory and a scroll function a presentation of the contents of a complete coded text line is possible. A further embodiment of the system is characterized in that the receiver is provided with entry means for manually entering scroll commands, the display control means being adapted to control the scrolling in dependence on the entered scroll commands.
This embodiment has the advantage that the user himself can initiate a scroll of the coded text line stored in the memory each time when he finds this desirable.
A further embodiment of the system is characterized in that the display control means are adapted to scroll the characters with a speed dependent on the scrolling control codes or the entered scrolling commands.
This embodiment enables an adaption of the scrolling speed on specific circumstances.
An other embodiment of the system is characterized in that the control codes comprises marking codes for marking groups of characters, the display control means being provided with means for selecting the character codes for which corresponding characters are to be displayed on the basis of the marking codes.
This embodiment enables the presentation of the most significant words of a message on the display.
Preferably the groups of characters (character strings) to be displayed are placed between a start code and a pause code. In that event it is preferred to use a system, characterized in that the display control means are adapted to cause a display of a space-type character in response to a pause code, whilst no display of corresponding character is caused for the start codes.
This embodiment enables a very suitable separation on the display unit between character strings which are not subsequent in the message defined by the coded text line.
A further embodiment of the system is characterized in that the sub information comprise text packets, each text packet comprise a coded text line and additional control codes, a part of the text packets comprises an indicating control code indicating that the corresponding packet comprises a coded text line with text information to be displayed on the display unit with the limited display positions, the receiver is provided with means for preselecting text packets having a indicating control code, and means for exclusively supplying preselected text packets to the display control means.
By the use of the pre-selection it is prevented that the display control means makes unnecessary searches in coded control lines which does not include characters to be displayed on the 1-line display unit.